Open the Vaults

Return all artifact and enchantment cards from all graveyards to the battlefield under their owners' control. (Auras with nothing to enchant remain in graveyards.)

Mobile Garrison

Whenever Mobile Garrison attacks, untap another target artifact or creature you control.
Crew 2 (Tap any number of creatures you control with total power 2 or more: This Vehicle becomes an artifact creature until end of turn.)

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.

Voltaic Key

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)

Sculpting Steel

You may have Sculpting Steel enter as a copy of any artifact on the battlefield.

Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

Trench Gorger

Trample
When Trench Gorger enters, you may search your library for any number of land cards, exile them, then shuffle. If you do, Trench Gorger has base power and base toughness each equal to the number of cards exiled this way.

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)